Pneumtic false twister



Feb. 1967 E. P. CARTER ET AL 3,303,639v

PNEUMATIC FALSE TWISTER Filed June 23, 1965 Ara INVENTORS E. R CART R. S. OTST United States Patent 3,303,639 PNEUMTIC FALSE TWISTER Ernest P. Carter, Durham, and Roger S. Otstot, Raleigh, N.C., assignors to Monsanto Company, St. Louis, M0., a corporation of Delaware Filed June 23, 1965, Ser. No. 466,159 6 Claims. (Cl. 57--77.3)

The present invention relates to apparatus for imparting a false twist or coiling action to continuous filaments. More particularly this invention relates to an improved pneumatic false twister.

In the preparation of yarns and fabrics for textile manufacturing purposes, the imposition of false twist on the fibers being processed is a very important and essential step in most operations. False-twist devices are commonly used in yarn bulking processes, core and sheathcore spinning processes, and production of non-woven structures. The false-twist may be produced by a mechanical or pneumatic type false twister. Recently there has been an increased amount of effort devoted to the improvement of the existing pneumatic false twisters because of an increased demand for non-woven structures. The pneumatic twisters are preferred over the mechanical twisters in the formation of various networks from continuous filament yarns since the air stream imparts a coiling action to the yarn and forwards it to a collection means where the yarn coils are bonded together to form a non-woven structure.

Heretofore, the pneumatic false-twist devices have been composed of air ejectors or aspirators having complicated design features which increase the difficulty of reproducing other units having similar operating performance. Therefore, it is difiicult to reproduce a controlled condition where several of the devices are employed. Another disadvantage with the presently known devices is the high velocities that are required in order to impart a minimum degree of twist to the yarn.

With the foregoing in mind, it is an object of the present invention to provide a device for imparting false twist to continuous filament yarn.

Another object of the invention is to provide an improved pneumatic false twisting device having simple design features and controllable operating ei'ficiency.

A further object of the invention is to provide a device which forwards yarn under low tension and imparts false twist thereto at a predetermined rate ranging preferentially from a low twist to an ultra-high twist.

Still another object of the invention is to provide an improved .pneumatic false twister capable of imparting a high degree of false twist to yarn under a considerable amount of tension.

Another object of the invention is to provide an improved pneumatic false-twist device capable of operating at low velocities to achieve low false twist.

Other objects and advantages of the invention will become apparent from the following detailed specification and the accompanying drawing.

One embodiment contemplated by the present invention comprises an elongated tubular body member having a hollow insert concentrically disposed in said body member and being characterized by a spiral-helical rib or fin extending around the outer surface of the insert and an inlet passageway through the wall of the body member for introducing a stream of air or other gaseous medium onto the spiral-helical fin which imparts a spiraling motion to the air as it passes over the fin on the insert to further impart a twisting action to yarn passing concurrently through the hollow insert.

The invention will be more clearly understood by reference to the drawings, in which:

FIGURE 1 is a side elevation of a preferred embodiment of the invention, partly in cross-section, to show the internal passageways of the device.

FIGURE 2 is a crosssectional view of the device shown in FIGURE 1 at 2-2.

FIGURE 3 is a cross-sectional view of another preferred embodiment of the invention wherein the air stream enters the body member intermediate the longitudinal axis thereof and is divided to flow in opposite directions.

Referring to FIGURE 1, there is shown a tubular member 10 which is designed to have a length substantially greater than the inside diameter. The member '10 has a counter-bore at one end to provide an annular shoulder 12 for accommodating an insert 14 disposed concentrically therein and supported by an enlarged disclike portion 16 which is secured against the shoulder 12. The insert extends through a major portion of the tubular member 10, but terminates at a point from the end opposite from the support flange 16 for reasons that will be explained later herein.

A spiral-helical rib 18 circumscribes the outer surface of insert 14 over the entire length thereof. The apex of the rib or fin 18 generally extends to within close proximity to the inside wall 20 of tubular member 10. It should be apparent however that the distance will be determined by the geometrical configuration of the fin 18 and its overall length, in conjunction with the pre ferred operating conditions to be explained hereafter. Thus, it is to be understood also that the depth, shape, and pitch of the fin 18 may be varied to give a wide range of twisting action whereby control of the twisting action can be attained at a predetermined air flow.

A passageway 22 extends throughout the longitudinal centerline of the insert 14 and support flange 16. The diameter of the passageway 22 is generally dimensioned to accommodate a continuous filament of the size normally used for fashioning non-woven structures. Positioned near the end of tubular member 10 which supports insert 14 is an inlet passageway 24 and a connecting conduit 26 for introducing a stream of air or some other gaseous medium into the bore of tubular member 10 from a source, not shown.

In operation of the embodiment described above, a filament is threaded through passageway 22. A gaseous medium such as air is introduced at inlet 24 and directed upon rib 18 which channels the medium in a coherent stream along the spiral-helical path to the end of insert 14 where the stream leaves the surface thereof with a spiraling action which contacts the filament and imparts false twist thereto. Also, as the air stream passes the end of insert 14 a suction is created at the yarn inlet 28 and thereby forwards the filament through the device.

The amount of false-twist and magnitude of force imposed upon the yarn may be controlled by either regulating the amount of air or changing the surface configuration of the insert 14 and its relationship with the inside wall 20 of tubular member 10. For example, when the spiral-helical fin 18 is in close proximity with the wall 20 an air stream having a low velocity will attain a spiraling motion as the stream advances to the end of insert 14 where the filament is entrained by a coherent stream of air which imposes a low degree of false twist and forwarding action on said filament.

Alternatively, if an ultra-high degree of false twist is desired for yarn being advanced :by mechanical driven rollers, another embodiment of the invention as shown in FIGURE 3 may be employed wherein a tubular member 30 having hollow insert 32 disposed therein is provided with an inlet 34 at midpoint between the ends thereof. The surface of insert 32 is provided with spiralhelical ribs 36 which are contiguous with the inside wall 38 of tubular member 30. A divider plate 40 is located opposite inlet 34 between insert 32 and inside wall 38 3 for dividing a source of air introduced through inlet 34. The ribs 36 and 37 circumscribe insert 32 in opposite directions to produce false twist on a filament advanced through passageway 42 at each end of tubular member 30 and thus impose an increased amount of twisting action on the yarn.

The foregoing detailed description has been given for clearness of understanding only, and unnecessary limitations are not to be construed therefrom. The invention is not to be limited to the exact details shown and described since obvious modifications will oconr to those skilled in the art, and any departure from the description herein that conforms to the present invention is intended to be included within the scope of the claims.

We claim:

1. Apparatus for imparting false twist to a continuous strand, comprising:

(a) a body member having an internal bore which is substantially unobstructed at one end thereof,

(b) a hollow member disposed in said bore, said member having a passageway for receiving a yarn to be false twisted,

(c) a screw thread-like configuration circumscribing said hollow member, and

(d) an inlet for introducing a gaseous medium into the internal bore wherein said thread-like configuration is adapted for directing said medium in a coherent stream having a coiling motion whereby false twist is imparted to said yarn.

2. Apparatus for imparting false twist to a continuous strand, comprising:

(a) a cylindrical member having an internal bore,

(b) an insert concentrically disposed in the bore and having a passageway therein for receiving a continuous threadline, said insert being secured to the cylindrical member at one end but terminating a distance from the other end thereof to allow ballooning of the continuous threadline, V

(c) a spiral-helical fin circumscribing the length of the insert in close proximity to the. bore wall, and

(d) an inlet located at said one end of the cylindrical member for introducing into said borera gaseous medium which imparts false twisting to .the continuous threadline.

3. An improved pneumatic false-twist device, comprising:

(a) a tubular member having a passageway extending through the length thereof, Y

(b) an insert disposed in the passageway for receiving a continuous threadline, said insert terminating a distance from one end of said tubular member,

(c) an inlet through a wall of the'tubular member for introducing a gaseous medium, and

(d) a surface configuration on the insert and adapted for advancing the gaseous medium in a coherent stream over the surface configuration thereby imparting a potential twisting action to said stream upon departure from said surface configuration which imposes false twisting on said continuous t hreadline.

4. An improved pneumatic false-twist device for imparting predetermined directional forces to a continuous strand, comprising:

(a) a cylindrical member having an internal bore,

(b) an insert disposed in the internal :bore, said insert having a spiral-helical fin extending longitudinally around the surface thereof and in close proximity to the wall of said bore,

(c) means for supporting the insert in the cylindrical member, said means and said insert having coextensively aligned passageways for receiving a continuous strand, and

(d) an inlet port for introducing a gaseous medium into the internal bore wherein said medium assumes the direction of a spiral-helix to impart false twisting to said continuous strand.

5. An improved pneumatic false-twist device for imparting a high degree of false twist to a continuous strand, comprising:

(a) a cylindrical member having an internal bore,

(b) an insert concentrically disposed in the internal bore and having a passageway therethrough for receiving a strand,

(c) an inlet port for introducing a gaseous medium into said bore,

(d) a plate located opposite the inlet port and disposed between said cylindrical member and said insert for dividing the gaseous medium, and

(e) spiral-helical fins circumscribing the insert and extending from said plate to the ends of said insert, said fins adapted to impart opposite twisting motions to the gaseous medium.

6. The device of claim 5 wherein the fins are contiguous with the internal bore wall.

References Cited by the Examiner UNITED STATES PATENTS 2,773,282 12/1956 Backer 5734 X 2,783,609 3/1957 Breen 57-34 X 2,924,000 2/1960 Greset et al. 57-34 X 2,990,671 7/1961 Bunting et al. 5777.3 X 3,022,566 2/1962 Daniels et al. 57-34 X 3,204,396 9/1965 Foster et al. 57-773 X 3,217,482 11/1965 -Baer 57-34 X FOREIGN PATENTS 787,285 12/1957 Great Britain. 1,137,609 1/ 1957 France.

STANLEY N. GILREATH, Primary Examiner. D. E. WATKINS, Examiner. 

1. APPARATUS FOR IMPARTING FALSE TWIST TO A CONTINUOUS STRAND, COMPRISING: (A) A BODY MEMBER HAVING AN INTERNAL BORE WHICH IS SUBSTANTIALLY UNOBSTRUCTED AT ONE END THEREOF, (B) A HOLLOW MEMBER DISPOSED IN SAID BORE, SAID MEMBER HAVING A PASSAGEWAY FOR RECEIING A YARN TO BE FALSE TWISTED, (C) A SCREW THREAD-LIKE CONFIGURATION CIRCUMSCRIBING SAID HOLLOW MEMBER, AND (D) AN INLET FOR INTRODUCING A GASEOUS MEDIUM INTO THE INTERNAL BORE WHEREIN SAID THREAD-LIKE CONFIGURATION IS ADAPTED FOR DIRECTING SAID MEDIUM IN A COHERENT STREAM HAVING A COILING MOTION WHEREBY FALSE TWIST IS IMPARTED TO SAID YARN. 